New FM1 build not booting inside chassis

Hey guys, I have been putting together a build for my dad and I wanted to go with the AMD Fusion chips since he doesn't require a separate GPU, but still needed a decent graphics capability for editing videos and such. Anyways, I went with the Foxconn A75A motherboard originally. The build did not boot when all the components were in, and the PSU tested fine. We RMAed the board and got the GIGABYTE GA-A75-UD4H FM1 AMD A75 motherboard instead. When outside the chassis, the motherboard boots up with all the components connected. When I screw the motherboard onto the standoffs, it no longer boots. At first I figured it was a problem with the screws not having plastic washers between them and the holes to the standoffs, but even after putting a plastic washer on each of the holes, it still won't boot up. I short the two two prongs to do a Clear CMOS and when I press the power button, everything lights up for about 1/10 second, and immediately turns back off. All the standoffs are used, and I can't see any metal touching the motherboard. I'm at a complete loss. It is my dad's work computer, so I've been a bit rushed to get it together so he is able to continue working, but I've been troubleshooting for nearly a week now. Any ideas?

Here's the build:

COOLER MASTER Storm Scout SGC-2000-KKN1-GP Black Steel / Plastic ATX Mid Tower Computer Case
GIGABYTE GA-A75-UD4H FM1 AMD A75 (Hudson D3) SATA 6Gb/s USB 3.0 HDMI ATX AMD Motherboard
COOLER MASTER eXtreme Power Plus RS700-PCAAE3-US 700W ATX 12V v2.3 Active PFC Power Supply
AMD A8-3870K Unlocked Llano 3.0GHz Socket FM1 100W Quad-Core Desktop APU (CPU + GPU) with AMD Radeon HD 6550D
G.SKILL Ripjaws X Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866 (PC3 14900) Desktop Memory Model F3-14900CL9D-8GBXL
SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner - Bulk - OEM
Rosewill RCR-IC002 74-in-1 USB 2.0 3.5" Internal Card Reader w/ USB port / Extra silver face plate

I'm practically pulling my hair out from frustration. I must be overlooking something. I would greatly appreciate any help you guys have to offer. Thanks in advance!
3 answers Last reply
More about build booting inside chassis
  1. Hello,

    Are you sure you didn't miss a standoff? Thats the only reason I can think of why your board won't boot up if it boots up fine outside the case.

    Sometimes a standoff can be out of place causing a short on the motherboard. Make sure you only put standoffs where the motherboard has holes. You shouldn't put standoffs in ALL the holes on the motherbard.
  2. Support for AMD A8-3870K is listed in the mobo in Since BIOS Version F7, however A8-3850 since BIOS f2? which bios version does your mobo come up with?

    (that .100 extra ghz may have screwed you does you dad overclock? why did you buy the K unlocked version and why the 700wat PSU, try to build balanced components and not overkill)

    Also here is screenshot with the required standoffs to get filled.

    so a couple of stuff:

    1) balanced build = stable buils

    2)400-500 PSU watt would be more than enough

    3) 8+2 mobo VRM, bro i dont know about you, but i have 3+1 vrm my APU is running fine, i highly recommend 4+1 VRM for everything, but 8+2 is an overkill for 100wat CPU (if you put external graphic card, the APU will run on 65 Watt tdp and disable the internal graphic card.)

    4) Also the ram is not JEDEC standard, check if gigabyte have an feature to press something on the mobo to reset the ram frequencies, please note AMD motherboard does not support XMP profile, meaning special timing will not work, i dont know why all the other folks are hyped of getting all there equipment overclock and non standard, but that reduces the system stability greatly, just like in your case, jumping in the normal zone, and most frequent usage of 9-9-9-24, 1.5volt, never hurted anybody.
  3. I'm not entirely sure, but the culprit could be your case. Have you tried different cables(case to mobo)? You should try placing your case on top of a rubber pad and make sure it's touching nothing.
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